As of today, Microsoft won't allow manufacturers to install XP on new netbooks," says blogger Kevin Fogarty. "That doesn't mean corporate customers who special-order hardware with XP won't be able to get it, or even that its market share ( 60 percent!) will drop any time soon.... It just means XP has taken the first babystep toward obsolescence and the long (really long, considering its market share) slide down toward the pit of minor operating systems like the MacOS X (4.39 percent) , Java ME (.95 percent) and "Other" (which I think is an alternative spelling for "Linux" (.85 percent).

Is it still illegal to pirate software if the company making it stops selling and supporting it?

If the place where you live has laws against software piracy, then yes. I've not heard of anywhere with anti-piracy laws that also has an exception for this case. That being said, I doubt most companies would go after anyone for pirating what isn't even sold to them anymore, but that doesn't make it any less illegal.